In a quiet corner of B.C., a mine that shut down 60 years ago has been slowly leaking acid runoff into a river that flows into Alaska.

Officials there are working to change that.

In 1957, the Tulsequah Chief mine on the shores of the Taku River in northwest B.C. closed its doors, leaving behind acid mine drainage — the acidic water created at mining sites that can then drain into waterways, which critics say can harm fish and other wildlife.

The drainage is a big concern for Alaskans given the location of the mine — next to one of the most important salmon rivers in the U.S.

The Alaskan government has tried dozens of times to compel B.C. officials to do something about the drainage since the mine closed.

Acid drainage from the Tulsequah Chief Mine on the Tulsequah River in British Columbia. (Chris Miller)

But the small mine has also become a symbol of larger problems with the security deposits that mining companies have to give the province, which are meant to cover cleanup costs should the company unexpectedly close shop.

Two companies have owned the Tulsequah Chief mine in recent history — Redfern Resources and Chieftain Metals. Both were put into creditor protection, the latter in 2016.

In both cases, the companies had obtained their exploration permits while promising to cleanup the acid mine drainage.

Chieftain Metals installed and had begun to operate a new water treatment plant on the site when it took over ownership, but the company's bankruptcy signaled that, once more, Alaskans would have to wait.

A persistent problem

Alaskan senator Dennis Egan no longer counts the letters he has sent over the last 20 years to try and put more pressure on B.C.

"Our community's not against mining. I have two mines in my district," he said.

"They're doing it correctly, because they have all these restrictions on what they do on exploration and tailings disposal, things like that, that weren't required on Tulsequah," he said.

For Egan and his fellow senators, it's as much an economic problem as an environmental one. The Taku supports five different species of salmon.

According to a study published last October by research firm McDowell Group, the seafood industry and sport fishing on the river brings in $9.6 million each year.

'This is how B.C. does mining'

In August 2015, Alaskans thought they were closer to their goal when B.C. Mining Minister Bill Bennett flew over the region in a helicopter.

That is until Bennett addressed the matter in question period.

"Those studies so far have shown that there isn't significant environmental harm being done," Bennett said at the B.C. legislature in March.

That's not how Chris Zimmer, director of Rivers Without Borders, sees it.

"Every inspection by the B.C. and Canadian ministries has found contamination," Zimmer said.

"But now the question of harm. What I see the minister saying is, 'Well it's not an emergency right now, so we're not going to clean it up and we're going to go do some studies to see if the acid mine drainage is harming the river.'"

View of the Tulsequah River looking east towards the confluence with the Taku River. (Chris Miller)

He also worries that, with the growing number of mining projects in B.C., the province could be ill-equipped in case of disaster.

"People here in southeast Alaska look at the Tulsequah Chief as, 'This is how B.C. does mining,'" he said.

"And if we can't deal with the acid mine drainage problem at this smaller mine, how are we going to deal with bigger problems?"

The province declined to comment on the matter.

$1-billion shortfall

After the bankruptcy of Chieftain Metals, the province ordered a report to evaluate the risks of the mine as well as an engineering report on cleanup of the site, which should come out this fall.

The province will then determine what it will do to clean up the site. In the meantime, it is still looking for a potential buyer.

Calvin Sandborn, director of the Environmental Law Centre at the University of Victoria, says if that option doesn't present itself there are few other options available.

Chris Zimmer leads the Rivers Without Borders in Alaska. He says more needs to be done to protect the state's rivers from environmental problems caused by B.C. mines. (Simon Charland/CBC)

One is to use the cleanup deposit that mining companies pay. But in the case of the Tulsequah Chief, the $1.2 million deposit isn't enough to clean it up.

That's a concern B.C.'s auditor general revealed last spring, when she said mining companies have not provided government with enough financial security deposits to cover potential reclamation costs if a firm defaults on its obligations.

Sandborn said, in theory, the province could also sue the company to force it to clean up the site.

Otherwise, the province could either pay the cleanup bill itself or try to get the first owner of the mine, Teck (then called Cominco), to clean up the site.

New bill put forward

Bennett, the main contact between Alaska and B.C. on the matter, will not be running again in the upcoming provincial election.

Anticipating that change, the Alaska State Legislature's fishing committee is currently considering new options to push Canada to act.

Photo from a B.C. environmental inspection report on the Tulsequah Chief mine, showing where acidic discharge is released into the Tulsequah River. (B.C. Ministry of Energy and Mines)

It's preparing a bill calling on the U.S. to work with Canada "to investigate the long-term, region-wide downstream effects of proposed and existing industrial development and to develop measures to ensure that state resources are not harmed by upstream development in British Columbia."

A hearing for the bill is scheduled for Thursday.

Corrections

An earlier version of this story said the Taku is the only river in the U.S. which supports five species of salmon. In fact, other rivers such as the lower Alaskan portion of the Unuk river also support five species of Pacific Salmon.